Microbial air sampler integrating media plate and sample collection device

Abstract

The invention generally provides devices and methods for sampling, detecting and / or characterizing particles, for example, via collection, growth and analysis of viable biological particles such as microorganisms. Devices and methods of the invention include particle samplers and impactors for collecting and / or analyzing biological particles in manufacturing environments requiring low levels of particles, such as cleanroom environments for electronics manufacturing and aseptic environments for manufacturing pharmaceutical and biological products, such as sterile medicinal products. Devices and methods of the invention incorporate an integrated sampler and impact surface, such as the receiving surface of a growth media, in a manner to minimize, or entirely eliminate, risks associated with user handling, such as the occurrence of false positive determinations due to contamination of the impact surface during particle sampling, growth or analysis processes.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority from Italian Patent Application No. RM2013U000128, filed Jul. 23, 2013, and U.S. Provisional Patent Application No. 61 / 953,128, filed Mar. 14, 2014, each of which is hereby incorporated by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.BACKGROUND OF INVENTION[0003]This invention is in the field of particle sampling, collection and analysis. The invention generally relates to devices and methods for sampling and characterizing particles in fluids including air and process chemicals (e.g., gases and liquids) for applications including the evaluation of contaminants in a range of cleanroom and manufacturing environments.[0004]Cleanrooms and clean zones are commonly used in semiconductor and pharmaceutical manufacturing facilities. For the semiconductor industry, an increase in airborne particulate concentration can result in a decre...

AI Technical Summary

Benefits of technology

[0011]The invention generally provides devices and methods for sampling, detecting and / or characterizing particles, for example, via collection, growth and analysis of viable biological particles, such as microorganisms. Devices and methods of the invention include particle samplers and impactors for collecting and / or analyzing biological particles in manufacturing environments requiring low levels of particles, such as cleanroom environments for electronics manufacturing and aseptic environments for manufacturing pharmaceutical, biological and medical device products, such as sterile medicinal products. Devices and methods of the invention incorporate an integrated sampler and impact surface, such as the receiving surface of a growth media, in a manner to minimize, or entirely eliminate, risks associated with user handling, such as the occurrence of false positive determinations due to contamination of the impact surface during particle sampling, growth or analysis processes.

[0012]In some aspects, the invention provides a particle impactor device having an integrated sampler and enclosed impact surface designed for single use and / or disposable use, thereby eliminating the costs and contamination risks involved with reuse. Particle impactor devices of the present invention having an integrated sampler and enclosed impact surface are capable of achieving effective sampling and growth of biological particles while minimizing the incidence for user contamination during handling and use. Particle impactor devices of the present invention having an integrated sampler and enclosed impact surface are also capable of effective sterilization in a fully assembled configuration wherein the impact surface, such as the receiving surface of a growth medium, is maintained in an enclosed configuration during the sterilization process, thereby eliminating the need for a user to access the impact surface prior to particle sampling. The invention also provides optically transparent particle impactors capable of in situ optical and / or visual analysis of particles, such as viable biological particles, without the need for physical access or handling of the impact surface during sampling, growth and optical characterization of viable biological particles.

[0020]In an embodiment, for example, the outlet of the impactor base is connected to a fan or pump for providing the fluid flow through the impactor, wherein the flow changes direction after passing through the intake apertures. In an embodiment, for example, the direction of the fluid changes by more than 20 degrees after passage through the intake apertures, and optionally more than 40 degrees after passage through the intake apertures. Implementation of a change in the direction of the fluid flow after passage through the intake apertures is useful for providing high efficiency collection of particles having preselected cross sectional dimensions, e.g., diameter or effective diameter greater than or equal to a threshold value.

[0021]The invention includes impactors comprising optically transparent components, for example, to allow for efficient use in a fully assembled configuration. In an embodiment, for example, at least a portion of the impactor base, sampling head or both are optically transparent to allow characterization of the particles on the impact surface without disengaging the sampling head and the impactor base. In an embodiment, for example, the impactor base, sampling head or both are optically transparent so as to provide a transmission greater than or equal to 50% for at least a portion of incident light having a wavelength from the range of 400 nm to 800 nm. In an embodiment, for example, the impactor base, sampling head or both are optically transparent so as to allow visualization, optical detection or imaging of particles on the impact surface without disengaging the sampling head and the impactor base. In an embodiment, for example, the impactor base, sampling head or both are optically transparent so as to allow determination of the amount of viable biological particles on the impact surface. In an embodiment, for example, the impactor base, sampling head or both are optically transparent so as to allow determination of the genus or species of viable biological particles on the impact surface.

[0022]The impactors of the present invention may include a range of additional structural features to facilitate effective use and avoidance of contamination. In an embodiment, the impactor base has a plurality of grooves provided on an outer surface to allow for effective handling of the impactor by a user, for example, by providing an exterior surface allowing for a user to easily transfer the device to and from a sampling environment. In an embodiment, the impactor base has one or more recessed features to allow for effective stacking of a plurality of the impactors, thereby minimizing the potential of the stacked impactor to fall and potentially become damaged or contaminated during transfer to and from a sampler.

[0026]In some embodiments, methods and devices of the invention provide a benefit of minimizing, or entirely eliminating, the need for a user to physically access the impact surface after sterilization. In an embodiment, for example, the method does not include a user physically contacting the growth medium after being contacted with the particles. In an embodiment, for example, a method of the invention further comprises the step of providing a cover on the sampling head for covering the intake apertures, thereby sealing the growth medium within the device after the sampling step.

Problems solved by technology

For the semiconductor industry, an increase in airborne particulate concentration can result in a decrease in fabrication efficiency, as particles that settle on semiconductor wafers will impact or interfere with the small length scale manufacturing processes.

For the pharmaceutical industry, where this type of real-time efficiency feedback is lacking, contamination by airborne particulates and biological contaminants puts pharmaceutical products at risk for failing to meet cleanliness level standards established by the US Food and Drug Administration (FDA) and other foreign and international health regulatory agencies.

For example, the collection efficiency may be of high importance, as failing to detect that biological particles are present in cleanroom air can result in the cleanroom environment having higher levels of contamination than detected.

Upon determination that under counting has occurred, pharmaceutical products made in those environments can be identified as failing to meet required standards, potentially leading to costly product recalls.

Similarly, failing to ensure that the viability of collected biological particles is maintained during the collection process will also result in under counting.

Such a situation can arise, for example, if the collected biological particles are destroyed, damaged or otherwise rendered non-viable upon impact with the growth medium, such that the collected particles do not replicate during the incubation process and, therefore, cannot be subsequently identified.

Over counting of this nature arises where a biological particle that is not collected from the cleanroom air, but is otherwise placed in contact with the growth medium, is allowed to replicate during the incubation process and is improperly identified as originating from the cleanroom air.

Situations that contribute to false positives include failing to properly sterilize the growth medium and collection system prior to particle collection and improper handling of the growth medium by cleanroom personnel as it is installed into a particle collection system and / or removed from the particle collection system and placed into the incubator.

Again, this can result in a pharmaceutical product being identified as failing to meet required standards.

Without sufficient measures to identify false positives, such a situation can result in pharmaceutical products that actually meet the required standards, but are destroyed due to an overestimation of biological particle concentration in the cleanroom air indicating that the standards were not met.

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